Power Input
Power is applied to the primary of transformer T1501 through Line Fuse F1501, POWER switch S1501, Thermal Cutout S1502, Line Voltage Selector switch S1503, and the Regulating Range Selector Assembly. Line Voltage Selector switch S1503 connects the split primaries of T1501 in parallel for 115-volt nominal operation, or in series for 230-volt nominal operation. Line Fuse F1501 should be changed to the correct value to provide the correct protection for each nominal line voltage current rating of...
Secondary Circuit
The 8 volt, 5 volt, 15 volt, and 55 volt supplies are series-regulated supplies. U1524A and B and U1554A and B are high-gain amplifier cells with differential inputs. These amplifiers monitor voltage variations in the output voltages. For SN B080000 and up, a regulated 110 V supply is provided in addition to the unregulated 120V supply. Both are derived from the terminal 14, 15, and 16 winding of T1501 and the full wave bridge rectifier CR1511. The 110 V regulated supply is referenced to the 55...
B Sweep Latch
0822 and Q828 compose the B Sweep Latch. Quiescently, before either the A or B Sweeps have reached their maximum amplitudes both transistors are off. Then, the sweep reset pulse from whichever sweep terminates first will be applied to the base of Q828 A Sweep reset through CR826 B Sweep reset through CR825 .The positive-going reset pulse turns on Q828 and the negative-going movement at its collector turns on Q822. The collector of Q822 in turn pulls up on the base of Q828, holding Q828 on,...
Paraphase Amplifier
U640 is a paraphase amplifier stage that converts the single-ended input from Source Follower Q622 into a push-pull output applied to the tunnel diode driver stage. Trigger Level Centering adjustment R635 sets the level at pins 14 and 15 of U640 so that the display is correctly triggered when the LEVEL control is centered. The LEVEL control varies the level at pins 14 and 15 of U640 to select the point on a trigger signal where triggering occurs. The slope of the input signal that triggers the...
DC Restorer Circuit
C1488, C1487, CR1487, CR1488, and R1486 form a DC restorer circuit. All DC levels in this circuit are referenced to the negative potential of the CRT cathode. The voltage difference across R1486 approximately equals the voltage swing present at the junction of CR1482 and CR1483. The control grid end of R1486 is more negative than the end connected to CR1488. The amplitude of the voltage swings present at the junction of CR 1482 and CR1483 is determined by the voltage levels established by the...
XAxis Amplifier
In all positions of the TIME DIV switches except X-Y, the input signal to the base of Q1224 will be the sawtooth waveforms from the sweep generators. In the X-Y mode however, the sweeps are disabled and the signal applied to Q1224 comes from the Channel 1 Preamp via the X-Axis Amplifier stage. This stage includes Q1214, Q1218, and their associated circuitry. Fig. 3-7. Detailed block diagram of the Horizontal Amplifier. Fig. 3-7. Detailed block diagram of the Horizontal Amplifier. Q1214 is...
Third Cascode Amplifier
Q132 and Q134, in conjunction with Q304 and Q308 in the Vertical Switching Circuit, form the Third Cascode Amplifier stage. Thermistor RT131 between the emitters of Q132 and Q134 changes in value with changes in temperature. This varies the gain of the Third Cascode Amplifier stage to compensate for changes in total amplifier gain that occur with variations in operating temperature. The push-pull signals picked off in the emitters of Q132 and Q134 are converted to a single-ended signal by Q142...
Obtaining Replacement Parts
Standard Parts. All electrical and mechanical part replacements for the 465 can be obtained through your local TEKTRONIX Field Office or representative. However, many of the standard electronic components can be t obtained locally in less time than is required to order them from Tektronix, Inc. Before purchasing or ordering replacement parts, check the parts list for value, tolerance, rating, j and description. When selecting replacement parts, it is important to remember that the physical size...
A and B Sweep
Determines the operating mode for the A Trigger Circuit. AUTO With the proper trigger control settings, A Sweep can be initiated by signals that have repetition rates above about 20 hertz and are within the frequency range selected by the COUPLING switch. In the absence of an adequate trigger signal or when the trigger controls are misadjusted, the sweep free-runs to produce a reference trace. NORM With the proper trigger control settings, A Sweep can be initiated by signals that are within the...
HighVoltage Rectifiers and Output
The high-voltage transformer T1420 has two output windings. One winding provides filament voltage for the cathode-ray tube. The filament voltage can be supplied from the High-Voltage Supply, since the cathode-ray tube has a very low filament current drain. The cathode and filament of the CRT are connected together to elevate the filament and prevent cathode-to-filament breakdown. One high-voltage winding provides both the negative cathode potential and the positive anode accelerating voltage....
Horizontal Sweep Controls
TIME DIV Switches A TIME DIV VAR HORIZ DISPLAY Switch X10 MAG Switch POSITION Control Locked together at 1 ms Calibrated detent A 1. Set the POWER switch to on button out . Allow several minutes for instrument warmup. 2. Connect the external signal to the CH 1 input connector. 3. Advance the INTENSITY control until the display is visible. If the display is not visible with the INTENSITY control at midrange, press the BEAM FIND pushbutton and adjust the CH 1 VOLTS DIV switch until the display is...
Cabinet
Index Tektronix Serial Model No. No. Part No. Eff Dscont 437-0141-00 348-0080-01 352-0263-00 200-1412-00 200-0602-00 367-0140-03 334-1998-00 214-0516-00 214-0513-00 214-0513-04 214-0515-00 214-0515-02 2 COVER,HINGE 80009 1 HANDLE, CARRYING 80009 4 SCREW,MACHINE 6-32 X 0.50 100 DEG,FLH STL 83385 OBD 2 SPRING,HLCPS 0.959 DIA X 1.250 INCH LONG 80009 2 INDEX,HDL RING 80009 2 INDEX,HDL RING 80009 2 GEAR,HDL INDEX 80009 2 GEAR,HDL INDEX 80009 1 WASHER,FLAT 0.204 ID X 0.438 INCH OD,STL 12327 1...
Cabinet Removal
Dangerous potentials exist at several points throughout this instrument. When the instrument is operated with the cover removed, do not touch exposed connections or components. Some transistors may have elevated cases. Disconnect power before cleaning the Instrument or replacing parts. The instrument wrap-around cabinet can be removed in the following manner 1. Unwrap the power cord from the instrument feet. 2. Remove the six screws indicated in Fig. 4-1 and remove the instrument feet and rear...
Second Cascode Amplifier
Transistors Q102-Q122 and Q104-Q124 constitute the Second Cascode Amplifier stage of the Channel 1 vertical preamplifier. Gain adjust R118 sets the overall gain of the Channel 1 vertical preamplifier by adjusting the signal current into the emitters of Q122 and 0124. The VAR control R112, when rotated out of the calibrated detent position, also adjusts the signal currents into Q122 and Q124 to provide uncalibrated deflection factors between the calibrated settings of the VOLTS DIV switch....
Second Cascode Amplifier 1
The Second Cascode Amplifier in Channel 2 is basically the same as the Second Cascode Amplifier in Channel 1 except that the Channel 2 INVERT switching takes place here. For a normal non-inverted display, 5 volts is connected to the bases of transistors Q222 and Q224 by INVERT switch S225. The voltage divider comprised or R225 and R226 applies approximately 2.5 volts to the base of Q226 and Q228. Q222 and Q224 are biased on and Q226 and Q228 are biased off, and the signal passes on to the...
General Sxe
The fan motor used in the 465 is a brushless DC fan motor using Hall Effect devices. The fan motor circuitry varies the rotational speed of the fan with variations in operating temperature. When the ambient temperature increases, the value of thermistor RT1696 reduces. This biases Q1698 on harder to condi ct more current through the Hall devices. Higher currents through the Hall devices causes the potential difference across them for instance, between pins 6 and 8 of the fan to increase. This...
CRT Control Circuits
Focus of the CRT display is controlled by FOCUS control R1430. ASTIG adjustment R1445, which is used in conjunction with the FOCUS control to provide a well-defined display, varies the positive level on the astigmatism grid. Geometry adjustment R1442 varies the positive level on the horizontal deflection plate shields to control the overall geometry of the display. Two adjustments control the trace alignment by varying the magnetic field around the CRT. Y Axis adjustment R1446 controls the...
Calibrator and Power
A combination current loop and square-wave voltage output device. Provides a 30 mA square-wave current, 300 mV square-wave voltage signal with a repetition rate of approximately 1 kHz. Light that indicates the applied line voltage is below the lower limit of the regulating range selected by the Regulating Range Selector assembly. Output connector providing a positive-going rectangular pulse coincident with the A sweep time. Output connector providing a positive-going rectangular pulse...